Three-Dimensional Numerical Modeling of Flow and Algal Biomass Distribution in Lake Pontchartrain

摘要

This paper presents the development and application of a three-dimensional numerical model for simulating the flow circulations and algal biomass distribution in Lake Pontchartrain, LA. Water movements within the lake are primarily wind and tide-induced. In order to protect the city of New Orleans, the Bonnet Carre Spillway (BCS) was constructed to divert flood water from the Mississippi River into Lake Pontchartrain and then into the Gulf of Mexico. These flood release events may increase nutrients in the lake, and as a result, cause algal bloom and other environmental problems in the lake. In this study, a numerical model was developed based on the CCHE3D model for simulating flow and algal bloom distribution. This model is a finite element model utilizing a special method based on the collocation approach called the efficient element method. The developed model was first verified against analytical solutions of flow fields and mass transport, and then it was applied to simulate the flow and algal biomass distribution in Lake Pontchartrain. The model was calibrated using field measured data provided by USGS, and then it was validated by the BCS Opening Event in 1997. The simulated results were compared with filed data and satellite imagery.